This invention relates in general to the field of resilient seating pads, and more particularly to a resilient seating pad which promotes and assists exercise of the muscles and vertebrae in the lumbar region of a person""s spine.
The thoracic portion of the human spinal column is protected and strengthened by the rib cage and the large dorsal and pectoral muscles. Unfortunately, the lumbar region is not as ruggedly supported, having for support only the abdominal muscles, and small, short muscles which connect and interconnect the lumbar vertebrae and the sacral vertebra. For convenience, these small interconnecting muscles are hereafter referred to as the xe2x80x9clumbar cage.xe2x80x9d It appears that the lumbar cage evolved over the millennia when humans had a short life span and long hours of physical activity each day, but its structure is not well suited for modern man with a much longer life span and whose lifestyle is much more sedentary and inactive. This weaker region (lumbar) of the load-bearing muscular-skeletal structure of the human anatomy is the source of most lower back pain and is also a major factor in back pain associated with structural defects such as scoliosis, a lateral curvature of the spine, spinal stenosis or lumbar disc syndrome.
The strength of a muscle depends upon the amount of work it is required to perform over time. Since muscles can only contract, they are worked by causing them to contract or flex. To flex a bodily joint, certain muscles (flexor muscles) are contracted while opposing muscles (extensor muscles) are relaxed so they can be extended. To straighten the joint, the reverse happens: the extensor muscles contract and the flexor muscles relax. Extensor and flexor muscles of the lumbar cage provide the necessary movement of the lumbar vertebrae, allowing them to be extended and flexed to accommodate the body""s activity. These, as well as other muscles in the lumbar cage, are worked by contractions and extension to cause movement of a part or parts of the body, allowing the body to change position and, even while the body is relatively inactive, to maintain position and balance.
Reduced activity, which may result from age, a sedentary job, illness, trauma, or simply a lack of sufficient motivation to exercise, limits the flexion and extension of the lumbar cage, causing these muscles to weaken and atrophy to the point that the load-bearing capacity of the lumbar region becomes more and more limited. The weakening process is progressive and cyclical. As atrophy sets in from reduced muscle activity, the lumbar cage weakens. Eventually, torque or overload beyond the tolerance level of the weakened lumbar cage will either tear the fibers in one of the lumbar cage""s muscles or cause a vertebral disc to slip out of alignment, resulting in back pain and, in severe cases, disabling spasms. The pain results in even less activity and, therefore, further atrophy of the lumbar cage.
To defend against any muscular pain the body involuntarily uses other muscles to produce the required body movement, a process called substitution. A body with lower back pain naturally adopts a posture and gait, such as splayed feet, a shuffling movement with no working of the hamstrings, which minimize the natural activity of the lumbar cage. With this reduced activity caused by substitution, the lumbar region becomes weaker, less flexible and vulnerable to further muscle strain and disc displacement. Generally, along with deterioration in the strength and flexibility of the lumbar cage caused by a longer, less active lifestyle, posture is also negatively affected. Having a weakened lumbar cage tends to promote a bowed back and slumped shoulders when seated for long periods at a desk or in front of a computer.
Most people with lower back pain either cannot or will not exercise the lumbar cage adequately to produce the muscle strength necessary to eliminate the problem. Physical therapy for pain is, at best, for a limited time during the therapy session, and therefore is limited in effectiveness. This invention provides an easy, inexpensive and very convenient way for such people to exercise their lumbar cages whenever they are seated, at home or on the job. Its use enhances the tone of the lumbar cage. It enables a seated person to actively exercise the lumbar cage while promoting better posture.
Another major factor in maintaining an over all healthy lower back is avoiding idiopathic (degenerative disc) low back pain. Disc degeneration is irreversible structural alteration in the disc which can be caused by many factors, and results in the reduction in height, loss of hydrated flexibility, one of the forms of herniation, or spinal stenosis (a narrowing of the spinal annulus). Since the intervertebral discs are avascular, that is, they are without blood carrying capillaries, the pumping action from physical activity is the only means of promoting the exchange of fluids for improved nutrition of the cells, for cell replacement, and for removing metabolic by-products. Inactivity of the lumbar spine, caused by a sedentary life style or by the process of muscular substitution to prevent pain, can only accelerate the degenerative process within the discs. This invention produces the essential pumping action, repetitively and constantly during use, and amplifies and intensifies the pumping action so as to prevent, arrest, or decelerate the degenerative process.
Other advantages and attributes of this invention will be readily discernable upon a reading of the text hereinafter.
An object of this invention is to provide a seating pad which not only cushions but also provides a means for a person to exercise his or her lumbar cage while seated.
An additional object of this invention is to provide an adjustably tiltable lumbar cage flexor seat for supporting a seated person.
An additional object of this invention is to provide a tiltable lumbar cage flexor seat having a generally rigid platform supported by at least two selectively inflatable bladders.
An additional object of this invention is to provide a tiltable lumbar cage flexor seat having one inflatable bladder generally concentrically surrounding another inflatable bladder.
An additional object of this invention is to provide a tiltable lumbar cage flexor seat containing provision for storage of a hand pump for inflating the bladders.
A further object of this invention is to provide a tiltable lumbar cage flexor seat for improvement of a seated person""s posture.
These objects, and other objects expressed or implied in this document, are accomplished by a device having a rigid surface upon which a person sits upright, and an elastic support for the surface, the support allowing the surface to be rotated around two mutually orthogonal medians of the surface by selected movement of the person""s lower body. The medians are, for example, a front-to-back median and a lateral median. In this way the surface has two degrees of selective movement, e.g. pitch and roll. Preferably the elastic support includes a bladder assembly having a first elastic bladder inflated with a gas, and a second elastic bladder inflated with a gas, the second bladder circumscribing the first bladder. The bladder assembly is preferably centrally disposed beneath the rigid surface and is extensive to the margins of the surface. Preferably the bladders are each individually inflatable to selected pressures. This allows a user to make the first bladder stiffer to more effectively act as fulcrum for the rigid surface. Since the elastic support is a gas-filled bladder assembly, it has a reactive elastic force which remains substantially normal to the rigid surface regardless of the orientation of the surface with respect to the medians. It remains xe2x80x9csubstantiallyxe2x80x9d normal because when the rigid surface is tilted, a relatively small torque opposing the tilt is caused by the bladders trying to equalize the gas distribution therein. Preferably the invention further includes a base plate, the bladder assembly being sandwiched between the rigid surface and the base plate, a cover for enveloping the sandwich, and a gap in the second bladder for inflation access to the first bladder and optionally for storage of a pump. Preferably the first bladder is circular and the second bladder is toroidal, the toroidal bladder circumscribing the circular bladder, and the bladder assembly is centrally disposed beneath the rigid surface and extensive to the margins of the surface.